Makes Den's plugin story accurate and actionable for third-party authors.
- docs/PLUGIN_DEVELOPMENT.md: adds a "Plugin types & current status" section stating, honestly, which extension mechanisms work today — WebAssembly plugins (✅ work in a stock build via the
wasmbuiltin), compiled-in native plugins (✅ hook/command/completion API), and external native loading (🚧 scaffolded insrc/plugins/discovery.zigbut not yet wired into startup). Documents the WASM integer ABI, sandboxing, and theplugin.manifestkey=value format. - examples/plugins/wasm/plugin.manifest: adds a manifest alongside the existing runnable
math.zig/ README example.
Verified: den wasm math.wasm add 5 3 => 8; the module compiles with zig build-exe ... -target wasm32-freestanding.
Scope: docs + example only. Wiring PluginDiscovery into startup and adding a plugin builtin are intentionally left for a follow-up.